1. Technical Field
The present invention relates to an image processing device and a head mounted display apparatus including the same.
2. Related Art
A technique called Augmented Reality (AR) for adding information to a real environment and presenting the information using a computer is known. A technique for realizing such augmented reality is applied to not only head mounted display (HMD) apparatuses (for example, refer to JP-A-2010-146481) but image processing devices (for example, refer to “Handy A R: Markerless Inspection of Augmented Reality Objects Using Fingertip Tracking”) which display an image on the existing displays other than HMDs. The HMD disclosed in JP-A-2010-146481 allows the user to visually recognize a virtual panel formed by augmented reality as a virtual image and associates a position and a movement of a hand of the user with the virtual panel. Therefore, a technique for recognizing the hand of the user is necessary, and such hand recognition techniques are disclosed in “Handy A R: Markerless Inspection of Augmented Reality Objects Using Fingertip Tracking” and “The international Journal of Virtual Reality, 2009, 8(2): 7-12 Robust Hand Tracking Using a Simple Color Classification Technique”.
In “Handy A R: Markerless Inspection of Augmented Reality Objects Using Fingertip Tracking” and “The international Journal of Virtual Reality, 2009, 8(2): 7-12 Robust Hand Tracking Using a Simple Color Classification Technique”, when a hand of the user imaged by a camera is recognized, the color of the hand is defined in advance as a model color of the skin, a region of a color which matches with the defined model color is separated from the other regions, and the shape of this separated region is recognized as the hand of the user. Accordingly, the recognition accuracy of the hand of the user can be secured to some extent by increasing the model color of the skin defined as the color of the hand of the user or by providing a certain margin to a value of the matching determination. However, an image pickup state of the hand of the user may vary. For example, there are many cases where the illuminance around the hand of the user may be rapidly changed depending on changes in outside weather conditions at that time, changes in the irradiation state of the sunlight, the glare of reflected light or shadow, and the like. In such cases, the color of the hand does not match with the model color, which may decrease the recognition accuracy of the hand of the user. In a room, the above-described phenomenon may occur depending on illumination conditions. In addition, the color of the hand of the user varies depending on the race of a person and the individual people. Therefore, whenever the color of the hand of the user cannot be recognized, it is necessary that the model color, which is the reference for recognizing the hand of the user, be newly defined according to the color of the hand of the user. As a result, convenience deteriorates. Moreover, even when the model color is newly defined, the recognition accuracy may be decreased due to rapid changes in illuminance. Therefore, in head mounted displays and image processing devices to which augmented reality (AR) is applied, it has been required that the recognition accuracy of the hand of the user be increased. In addition, improvement in the versatility of a technique for detecting a hand of the user, reduction in cost thereof, and the like have been also desired.